Hepatitis C virus (HCV) is a major cause of chronic hepatitis worldwide (Choo, et al. (1989) Science 244, 359-362). Chronic hepatitis C may lead to severe sequelae, such as liver cirrhosis and hepatocellular carcinoma (Tomimatsu, et al. (1993) Cancer 72, 683-688; and Tremolada, et al. (1992) J. Hepatol. 16, 273-281). Although scientists have made important progress in understanding molecular mechanisms for HCV replication, few data are available regarding essential cellular factors required for HCV replication (Blight, et al. (2000) Science 290, 1972-1974; Kolykhalov, et al. (1997) Science 277, 570-574; and Lohmann, et al. (1999) Science 285, 110-113).